To do any signing operation through the PDF Signing API, you first need to require an access token. This access token is then used to authenticate yourself.

The client generates its own assertion by signing a JSON web token (JWT) that includes the Client ID. Nexus GO validates the assertion cryptographically with the public key specified in the setup, see Set up PDF Signing API in Nexus GO.

Authentication step-by-step

Generate an assertion. See below for more information.

The web application sends an authentication request to Nexus GO, including an assertion.

Nexus GO fetches the public key of the client and validates the assertion.

Nexus GO creates and returns an access token. The access token must then be included in any other API operation, to authenticate the user.